Starch of the wxsh1 genotype and products produced therefrom

ABSTRACT

A substantially pure starch extracted from a starch bearing plant having a waxy shrunken-1 genotype is disclosed. Maize is the preferred plant. The sols produced for such starch exhibits superior freeze-thaw stability compared to sols made from chemically modified starches. A thickener composition and foodstuff containing the starch are also disclosed.

This invention relates to starch and more particularly to starch whichhas been extracted from a plant having a waxy shrunken-1 (wxsh1)homozygous genotype.

Starch occurs in a variety of plants and is generally categorized basedon its plant source. For example, cereal starches are extracted fromcereal grains such as maize, rice, wheat, barley, oats and sorghum;tuber and root starches are extracted from plants such as potato, sweetpotato, arrowroot, yams and cassava; and waxy starches are extractedfrom plants such as waxy maize, waxy rice, waxy barley and waxy sorghum.

Generally, starch is comprised of two polymers, amylose and amylopectinwhich are intertwined to form a starch granule. Amylose is a linearpolymer of alpha 1-4 bonded anhydroglucose units while amylopectin is abranched polymer comprised of linear chains of alpha 1-4 linkedanhydroglucose units with branches resulting from alpha 1-6 linkagesbetween the linear chains.

Each starch bearing plant produces different percentages of amylose andamylopectin, different size granules and different polymeric weights forboth the amylose and amylopectin. These differences produce markedlydifferent properties in the starch.

Heretofore, the only way to affect the properties of starch was to treatthe starch physically and/or chemically.

It has recently been discovered that there exists a number of recessivemutant genes in starch bearing plants which have an affect on theproperties of starch and that by controlled breeding these mutant genescan be expressed.

Some of the mutant genes which have been identified in maize include thegenotypes: waxy (wx), amylose extender (ae)=-, dull (du), horny (h),shrunken (sh), brittle (bt), floury (fl), opaque (o), and sugary (su).Nomenclature for some of these mutant genes is based in part on theeffect these mutant genes have on the physical appearance, phenotype, ofthe kernel. It is also known that within these genotypes there are geneswhich produce starch with markedly different functional properties eventhough the phenotypes are the same. Such subspecies have genrally beengiven a number after the named genotype, for example, sugary-1 ) andsugary-2 (su2).

One combination of these mutant genes which has been found to possessutility is taught in U.S. Pat. No. 4,428,972 issued Jan. 31, 1984 toWurzburg et al.

It has now been discovered that a plant having a waxy shrunken-1 (wxsh1)homozygous genotype will produce a starch having freeze-thawcharacteristics which are comparable to chemically modified starch.

More specifically, it has been discovered that a sol comprising waterand starch extracted from a plant having a waxy shrunken-1 (wxshl)homozygous genotype produces freeze-thaw characteristics comparable tosols made from conventional chemically modified starch.

An advantage of such a novel starch is that it can replace chemicallymodified starches, thereby providing economic advantages.

In order to obtain substantially pure starch in accordance with thepresent invention, a plant which produces edible starch and has a waxy(wx) genotype is crossbred with a plant which produces edible starch andhas a shrunken-1 h1) genotype to produce a plant having a waxyshrunken-1 (wxsh1) homozygous genotype. The starch is then extractedfrom this plant. Both the crossbreeding step and the extraction step ofthe present invention are carried out in a conventional manner.

In order to prepare a sol in accordance with the present invention, aslurry is prepared which comprises water and an effective amount ofstarch extracted from a plant of the wxsh1 genotype and the slurry issubject to a cooking step. The slurry is cooked as necessary to providea thickener composition which exhibits freezethaw characteristicscomparable to sols made from commercially available chemically modifiedstarch. If the starch has been made "cold water swellable", then thecooking step can be eliminated. The preferred amount of starch used inthe slurry constitutes about 1 to 20% by weight of slurry. Generally,cooking entails raising the temperature of the slurry to above about thegelatinization temperature of the starch and subjecting the starch toenough shear such that the granules rupture and a paste is formed. It isnot necessary that all the granules rupture.

A sol or a thickener composition of the starch of the present inventionis added to a foodstuff in a conventional manner in order to impartfreeze-thaw characteristics to the foodstuff.

Alternatively, starch of the present invention is mixed with a foodstuffor a slurry comprising water and starch of the present invention ismixed with a foodstuff and the resulting mixture cooked to produce athickened foodstuff thereby providing the foodstuff with freeze-thawcharacteristics in accordance with the present invention. In order toreplace a chemically modified starch with the starch of the presentinvention, a replacement ratio of about 1:1, starch of the presentinvention:chemically modified starch, can be employed. Larger or smalleramounts of the starch of the present invention may be use to replace thechemically modified starch.

The term starch as used in the specification and claims means not onlythe substantially pure starch granules as extracted from a starchbearing plant but also grain products of the starch granule such asflour, grit, hominy and meal.

The term waxy shrunken-1 or wxsh1 genotype as used in the specificationand claims means not only the wxsh1 homozygous genotype, wxwxsh1sh1,which has been obtained by standard plant breeding techniques but alsothe wxsh1 genotype which has been moved to another portion of the plantgenome by translocation, inversion or any other method of chromosomeengineering to include variations thereof whereby the disclosedproperties of the starch of the present invention are obtained.

Any plant source which produces edible starch and which can be crossbredto produce a plant having a wxsh1 homozygous genotype may be used. Ithas been found that waxy maize, waxy rice, waxy barley and waxy sorghumhave the mutant waxy (wx) genes while the shrunken 1 (sh1) gene isobtained from cereal grains such as maize. Maize is the preferred plantsource. The shrunken-1 gene and the waxy gene are both reported to belocated on chromosome 9 of the maize chromosomes. See "DevelopmentGenetics", Volume 5, pages 1-25, 1984.

Generally, to obtain a starch bearing plant with both double recessivemutants of the wx and sh1 genotype, a plant of a wx mutant is crossedwith a plant having a wxsh1 mutant and thereafter inbred to obtain aplant homozygous in wxsh1. After the homozygous wxsh1 genotype isobtained, standard breeding techniques are used to obtain hybrid vigor.Hybrids are preferred because of their high starch yield compared toinbred lines. The method of crossing plants and of obtaining specificgenotypes in the offspring as well as breeding to obtain hybrid vigor iswell known.

Extraction of starch from the plant is well known and typically entailsa milling process. In accordance with the present invention, a wetmilling process is used to advantage to extract the corn starch from thecorn kernels. Corn wet milling comprises the steps of steeping andgrinding the corn kernel and then separating the starch from the othercomponents of the kernel. Prior to steeping, the kernels are subjectedto a cleaning process to remove any debris which may be present. Thiscleaning process is usually done at the wet milling plant. The kernelsare then steeped in a steep tank where the kernels are contacted with acountercurrent flow of water at an elevated temperature of about 120° F.and containing sulfur dioxide in an amount between about 0.1 to about0.2% by weight water. The kernels are maintained in the steep tank forabout 24 to 48 hours. Next, the kernels are dewatered and subject to afirst set of attrition type mills.

The first set of mills generally grind and rupture the kernels causingthe germ, corn oil, to be released from the rest of the kernel. Atypical attrition type mill used in commercial wet milling processes issold under the brand name Bauer. The released germ is then separatedfrom the other parts of the kernel by centrifugation. Throughout thegrinding steps of the wet milling process the kernel and the kernelcomponents are maintained in a slurry of about 40% by weight solids.

The remaining kernel components which include starch, hull, fiber andgluten, are subjected to a second set of attrition type mills such asthe Bauer Mill, to further grind the components and separate the hulland fiber from the starch and gluten. Hull and fiber are generallyreferred to as bran. Washing screens are used to separate the bran fromthe starch and gluten. The starch and gluten pass through the screenswhile the bran does not.

Next, the starch is separated from the protein. This step is done eitherby centrifugation or by a third grind followed by centrifugation. Acommercial centrifugation separator suitable for the present process isthe Merco centrifugal separator.

The slurry which contains the starch granules is then dewatered and theresulting granules washed with fresh water and dried in a conventionalmanner preferably to about 12% moisture.

In this manner, the substantially pure starch of the present inventionis extracted from a starch bearing plant of the wxsh1 genotype.

Alternatively to the drying step, the starch may be left in suspensionand subject to further modification.

Modification of the starch may also be performed on the dried starch.Typically, in order to change the physical and/or chemical structure ofthe starch granule, the starch is subject to any one or more of eightgeneral treatments. These treatments comprise bleaching, thin boiling,acid treatment, enzyme treatment, dextrinization or dry roasting,etherification, esterification, and crosslinking Starches which havebeen treated by any one or more of these eight treatments listed aboveare conventionally referred to as chemically modified starch.

Bleaching, often referred to as oxidation, is a modification which doesnot appreciably alter the granular structure of the starch. Oxidationdoes, however, tend to lighten the color of the granules and reduce theviscosity of the starch paste.

In order to bleach the starch of the present invention, a slurry ofstarch is prepared of about 5 to about 40% by weight starch. To theslurry sodium hypochlorite is added with about 6% available chlorine(free chlorine) and the slurry is held at about 110° F. for betweenabout 1 to about 20 hours. The slurry is then neutralized with sodiumbisulphite and the resulting granules are dewatered, washed and dried inconventional manner.

Such modification makes the starch of the present invention suitable forlaundry starch, paper coating and as a textile size.

In order to produce a thin boiled starch of the present invention, aslurry of starch is prepared of about 5 to about 40% by weight starch.To this slurry, a mineral acid is added and allowed to react with thestarch for about 1 to about 100 hours at about 90 to about 120° F withconstant agitation. Such a reaction is done below the gelatinizationtemperature of the starch. Subsequently, the solution is neutralized,dewatered, washed and dried in conventional manner.

Thin boiling leaves the granules intact and produces a starch productwhich has a slight reduced viscosity compared to the non-thin boiledstarch. If partial or total destruction of the starch granule is sought,the granule may be subjected to acid treatment.

In order to acid treat the starch of the present invention, a slurry ofstarch about 5 to about 40% by weight starch is prepared. This slurry isreacted with acid, generally a strong acid, at a temperature abovegelatinization temperature. Such a procedure is preferably carried outby jet cooking the slurry through a conventional jet cooker with orwithout acid already in the slurry and then allowing the slurry to reactwith the acid, adding acid if needed, for a desired period of time oruntil the desired dextrose equivalent (DE) is reached. The DE is roughlyproportional to the length of time for the reaction. Generally, such jetcooking destroys the starch's granular structure.

After acid treatment, the resulting slurry is neutralized, dewatered anddried. Such product may also be subject to conventional carbon treatmentand filtration prior to dewatering and drying. Another treatment whichdegrades the granular structure is enzyme treatment.

In order to enzyme treat the starch of the present invention, a slurryof starch is made up having about 5 to about 40% by weight starch. Tothis slurry, enzyme is added at the optimum pH and temperature for theenzyme. Some advantage is found by first jet cooking the slurry to openup the starch granules, cooling the slurry to optimum temperature forthe enzyme and then adding the enzyme. If the enzyme is jet cook stablethen the enzyme can be added to the slurry prior to jet cooking. Theslurry may also be treated with acid first to a low DE and then enzymetreated. After enzyme treatment, the product is dewatered and dried.Alternatively, the product may be subject to conventional carbonbleaching and filtration prior to concentration and/or drying.

In order to dextrinize or dry roast the starch of the present invention,acid is added to dry starch granules and the mixture is heated to atemperature of about 250 to about 350° F. for about 3 to about 72 hours.The product, once removed from the heat, is sold as is. The preferredacids are hydrochloric, phosphoric and any mineral acid. Such a methodcauses the partial breakdown of the granular structure.

In order to etherify the starch of the present invention, a slurry ofstarch is made up having about 5 to about 40% by weight starch. The pHof the slurry is adjusted to about 10 to about 12 preferably with sodiumhydroxide. Next, an etherification agent such as ethylene oxide orpropylene oxide is added to the slurry in an amount of about 1/2to about25% depending on the desired degree of substitution. The reactionconditions are held for about 5 to about 30 hours at about 70 to about120° F. The slurry is then neutralized with any known acid, dewatered,washed and dried.

In order to crosslink the starch of the present invention a slurry ofstarch is made up of about 5 to about 40% by weight starch. The pH ofthe slurry is adjusted to about 8 to about 12 preferably with sodiumhydroxide. Optionally, a salt may be added to the slurry to affectswelling of the granules. Then the slurry is reacted with a crosslinkingagent such as phosphorous oxychloride, trimetaphosphate salt, orepichlorohydrin at about 70 to about 120° F. for about 1/2to about 5hours. The length of time of the reaction will depend on the amount ofcrosslink agent used and the specific crosslinking agent chosen.

In order to esterify the starch of the present invention, a slurry ofstarch is prepared having about 5 to about 40% by weight starch. The pHof the slurry is then adjusted to about 8 to about 10 and anesterification agent is added to the slurry such as vinyl ester, acetylhalides, acid anhydrides like acetic anhydride, or succinic anhydride.The esterification agent is added slowly while maintaining the pH of theslurry. The reaction is continued for about 1/2to about 5 hours at about80 to about 120° F. Once the reaction is completed to the desired degreeof substitution, the slurry is neutralized, dewatered, washed and dried.

Any combination of these modifications may be employed on starch of thepresent invention.

It has been found that a sol comprising water and an effective amount ofstarch extracted from a plant of a wxsh1 genotype exhibits thickeningcharacteristics which makes the sol a good commercial thickenercomposition. Such thickener compositions are especially useful infoodstuffs.

The sol is prepared by forming a slurry of water and starch of thepresent invention and subsequently cooking the slurry thereby forming apaste. Preferably, the sol contains the starch of the present inventionin the amount of about 1 to about 20% by weight total sol. The slurry iscooked at a temperature of about 90° C. and above to provide thickeningcharacteristics prior to adding to the foodstuff. Cooking time is about10 minutes. The sol in accordance with the present invention need not becooked if the starch has already been subjected to a process which makesit cold water swellable. Cooking generally comprises raising thetemperature of an aqueous slurry of the starch of the present inventionto the gelatinization temperature of the starch and subjecting thestarch to shear such that the starch granules rupture and form a paste.

In order to prepare the thickened foodstuff, a sol made in accordancewith the present invention is combined with a foodstuff and thecomposition is cooked to the necessary degree to provide a thickenedfoodstuff. Conventional mixing is employed to combine the sol with thefoodstuff. Cooking of the sol and foodstuff composition is also carriedout in a conventional manner.

Alternatively, starch of the present invention is mixed with thefoodstuff or a slurry comprising the starch of the present invention andwater is mixed with a foodstuff and the resulting mixture is cooked tothe desired degree to obtain a thickened foodstuff. When the starchitself or a slurry containing the starch itself is mixed with afoodstuff, the resulting mixture must be cooked in order to provide athickened foodstuff. The mixing as well as the cooking is accomplishedin a conventional manner. Cooking is carried out at a temperature ofabout 90° C. and above. Cooking time is about 10 minutes but may varydepending on the amount of foodstuff present and the amount of shearthat the mix is subject to during cooking.

The sol of the present invention exhibits freeze-thaw characteristicswhich make it comparable to sols made from commercially availablechemically modified starch.

Foodstuff prepared in accordance with the present invention exhibitsfreeze-thaw characteristics compared to foodstuff made with chemicallymodified starches.

These and other aspects of the present invention may be more fullyunderstood with reference to the following examples.

EXAMPLE 1

This example illustrates the extraction of the starch of the presentinvention from a wxsh1 maize kernel produced by conventionalcrossbreeding and tests the starch to determine its variouscharacteristics. The tests as well as the results obtained therefrom aregiven in Table I below. The extraction process as well as the testprocedures followed are outlined following Table I below:

                  TABLE I                                                         ______________________________________                                                         Present Invention                                            Test               Sample A  Sample B                                         ______________________________________                                        Percent Protein (dry basis)                                                                      0.25%     0.44%                                            Percent Oil (dry basis)                                                                          0%        0%                                               Percent Amylose (starch basis)                                                                   0.6%      0.8%                                             DSC Gelatinization Temp.                                                                         70.8° C.                                                                         70.1° C.                                  Regular Brabender Amylogram                                                   Initial Rise       72.5° C.                                                                         71° C.                                    Heating Peak       610    BU     710   BU                                     Heating Final      220    BU     290   BU                                     Cooling Peak       300    BU     320   BU                                     Cooling Final      300    BU     320   BU                                     Acid Brabender Amylogram                                                      Initial Rise       75.5° C.                                                                         72.5° C.                                  Heating Peak       595    BU     670   BU                                     Heating Final      40     BU     50    BU                                     Cooling Peak       50     BU     50    BU                                     Cooling Final      50     BU     50    BU                                     Brookfield Viscosities (RPMs)                                                 10                 2100   cps    2400  cps                                    20                 1500   cps    1800  cps                                    50                 1060   cps    1200  cps                                    100                840    cps    960   cps                                    50                 1080   cps    1220  cps                                    20                 1550   cps    1850  cps                                    10                 2100   cps    2400  cps                                    Hercules Viscosity (RPMs)                                                     550                69.4   cps    60.9  cps                                    1100               53.94  cps    57.42 cps                                    1650               44.08  cps    52.78 cps                                    2200               39.15  cps    49.88 cps                                    1650               41.76  cps    59.52 cps                                    1100               48.72  cps    60.90 cps                                    550                62.46  cps    74.82 cps                                    ______________________________________                                    

Crossbreeding

In order to perform the crossbreeding process, typically maize plantshaving the mutant gene wx were cross-pollinated with maize plants havingthe mutant gene sh1. From the mature ears of some of these plants,kernels having wxsh1 homozygous genotype were produced. Such kernelswere used to produce starch in accordance with the present invention andto provide seed for future maize plants of the wxsh1 homozygousgenotype.

Extraction Process

The following extraction process was used to extract the starch from thekernel. Sample A was grown in a dent corn background, Ohio 48, whileSample B was grown in a dent corn background, W64A.

Steeping

Steeping was carried out by adding maize kernels to water having a 0.2%SO₂ content and holding the temperature of the steep water at 50° C. for48 hours. The steep water was circulated through the steep container.After the 48 hours of steeping, the kernels were dewatered and washedwith water.

Grinding and Separating

A mixture of 1:1 kernels to water in a weight ratio was prepared andadded to a Waring blender equipped with a dull blade. The Waring blenderwas put on grind for one minute to mill the starch. The resulting mashwas poured onto a 40 mesh screen and what passed through the 40 meshscreen was passed through a 200 mesh screen and subsequently through a325 mesh screen. The resulting filtrate contained starch and protein.That which did not pass through the first 40 mesh screen was put backinto the Waring blender with water in a 1:1 weight ratio. This time asharp blade was used and the Waring blender was set for one minute ongrind. The resulting mash was then subject to a 40 mesh screen and thenthe filtrate was subjected to a 200 mesh screen and finally to a 325mesh screen. The final filtrate from both the dull blade grind and thesharp blade grind were dewatered and contained starch and protein. Thestarch and protein were reslurried and subjected to up to three separatecentrifuges to separate the starch from the protein.

The final starch was then filtered and dried in an oven at 110° C.overnight to a moisture content of approximately 10%.

In this manner, starch was extracted from corn kernels in the lab.

The percent protein was determined by a standard Corn RefinersAssociation (CRA) method (Kjeldahl method).

The percent oil was also done using a standard CRA method by extractingthe oil from dry, ground kernels using carbon tetrachloride for sixteenhours.

The percent amylose was determined using standard colorimetric iodineprocedures wherein the starch is first gelatinized with sodium hydroxideand then reacted with an iodine solution and the resulting samplemeasured using a spectrophotometer in a 1cm cell at 600 nm against ablank of 2% iodine solution.

The DSC gelatinization temperature was measured using a scanningcalorimeter manufactured by Mettler Model No. 300 using a 30% solidstarch following the procedure outlined in the owner's manual for thatmodel.

Two Brabender amylograms were run; one in a non-acid environment and onein an acid environment. Both were run at 51/2% solids using a 90 gramsample with 125 gram cartridge at 100 RPM. The exact procedure used isoutlined in the Amylograph Handbook of the American Association ofCereal Chemists, 1982 edition at pages 17 and 18. The respective paddlefor the 90 gram cup was used. The difference between the acid and theregular Brabender was that 1.56 grams of glacial acetic acid was addedto the sample to drop the pH of the sample to about 3 prior to runningof the samples. Such acid test is used to show stability in acidconditions.

The initial rise was the temperature at which the pen moves away fromthe baseline.

Both acid and regular samples were subjected to identical heat profiles.The sample started at room temperature and the rapid heat mode of theinstrument was used to heat the sample to 50° C. Once 50° C. wasreached, the instrument was set at a controlled rate of heating, 11/2°C./minute, until a temperature of 95° C. was reached. The sample wasthen held at 95° C. for 30 minutes. During this period of heating, thehighest viscosity obtained by the sample was labeled Heating Peak. TheHeating Final was the last viscosity obtained by the sample at the endof the heating cycle. Next, the sample was cooled at 11/2° C. to atemperature of 50° C. The sample was then held at 50° C. for 30 :inutes.The largest viscosity measurement taken during this cooling cycle was,the Cooling Peak and the final viscosity at the end of the cooling cyclewas the Cooling Final.

Brabender curves are a well known tool for determining characteristicsof starch.

Brookfield viscosities, another well known measurement used foranalysing starch was measured for the starch of the present invention inTable I above. In order to run this test, the starch slurry as it camefrom the regular, non-acid brabender test was used for the Brookfieldtest.

A Brookfield viscometer Model RV was used following standard proceduresto obtain these values. The tests were run at 50 C. with each RPM beingrun for a twenty second time interval.

Hercules viscosities were run on a Kaltec Model No. 244RC (manufacturedAug. 31, 1975) following the procedure outlined in the operators manual.Each test was run at 75° F. using bob A. A 25 gram sample of starchpaste as obtained from the acid Brabender was used for this test.Hercules viscosities measured high shear resistance of starch in an acidenvironment.

EXAMPLE 2

This example illustrates the superior freeze-thaw stability of thepresent invention compared to commercially freeze-thaw stabilizers. Thisexample also illustrates the synergistic nature of the starch of thepresent invention.

                  TABLE II                                                        ______________________________________                                        Starch Samples       Freeze-Thaw Cycles                                       ______________________________________                                        1.  Native common maize* 0                                                    2.  Native wx maize*     1                                                    3.  Native shl grown in an Ohio 43                                                                     0                                                    4.  POLAR GEL 5* waxy maize                                                                            3                                                        chemically modified with                                                      acetyl anhydride and crosslinked                                              with phosphorus oxychloride                                               5.  POLAR GEL 10* waxy maize                                                                           3                                                        chemically modified with                                                      propylene oxide and crosslinked                                               with phosphorus oxychloride                                               6.  710 STABILIZER* common maize                                                                       3                                                        chemically modified with                                                      propylene oxide and crosslinked                                               with phosphorus oxychloride                                               7.  Native wxshl grown in a W64A                                                                       4                                                    8.  Native wxshl grown in an Ohio 43                                                                   4                                                    ______________________________________                                         *A commercial product sold by American Maize Products Company, Hammond,       Indiana. Samples 4, 5 and 6 are sold as commercial freezethaw stabilizers                                                                              

The starch in samples 3, 7 and 8 were extracted from the kernelfollowing the procedure outlined in Example 1 above.

In order to determine the freeze-thaw stability of samples 1-8 above, asol was prepared having a 5.5% by weight solids content (approximately5.5 grams of starch for 94.5 grams of water). After being subjected tothe Brabender test of Example I above; and to the Brookfield test ofExample 1; the sol was divided into five portions, measuring 5 mls. eachand placed in 15 ml. centrifugal test tubes. These tubes were placed ina rack. Then, one test tube was then remove from the rack and subjectedto centrifugation for 10 minutes at about 3400 RPM. If 30% by weight ofthe water in the sol was separated from the solid mass of the sol bycentrifuging, then the sample was deemed to have failed and the number 0entered into the righthand column of Table II above. After entrifugingone tube of each sample, the rack was placed in a freezer at 4° C. Afterabout 20 hours at 4° C., all tubes were removed and allowed to thaw bystanding at ambient conditions, generally about 4 hours. Then one tubewas removed and subjected to centrifuging as described above. If 30% byweight of the water in the sol was separated from the solid mass, thenthe sample was deemed to have failed and the number 1 was placed intothe righthand column of Table II above.

Such 24 hour procedure was repeated to obtain all the numbers in therighthand column of Table II above.

It is readily apparent from Table II above that superior results areobtained with the starch of the present invention compared to thecommercial starches and compared to chemically modified starches.

It is also readily apparent that the starch of the present invention hasa synergistic property. Starch obtained from a maize plant having thewaxy (wx) genotype has one freeze-thaw cycle and starch obtained from amaize plant having a shrunken 1 (sh1) genotype had zero freeze-thawcycles while starch of the present invention, a cross between a maizeplant having a sh1 genotype and a genotype had four freeze-thaw cycles.This is truly synergistic.

It is also readily apparent that a sol made in accordance with thepresent invention is characterized as having freeze-thaw characteristicscomparable to chemically modified starch.

It is also readily apparent that the sol of the present invention iscapable of withstanding more freeze-thaw cycle than a sol prepared withnative waxy starch.

EXAMPLE 3

This example illustrates preparing a thickener composition in accordancewith the present invention.

The starch of the present invention as extracted in Example 1 above ismixed with water in an amount to produce a slurry having 10% by weightstarch. The slurry when cooked at about 90° C. for ten minutes producesa thickener composition.

Example 4

This example illustrates preparing a lemon pie filling with the starchof the present invention.

The following ingredients and procedure is used:

                  TABLE III                                                       ______________________________________                                        Ingredients    % by Weight Present Invention                                  ______________________________________                                        Water          62.94                                                          Sugar          19.30                                                          Maltodextrin   6.67                                                           Present Invention                                                                            4.50                                                           Corn Syrup Solids                                                                            2.50                                                           Lemon Juice    2.50                                                           Vegetable Shortening                                                                         1.03                                                           Salt           0.23                                                           Citric Acid    0.20                                                           Emulsifier     0.10                                                           Lemon Oil (2x) 0.03                                                                          100.00                                                         ______________________________________                                    

Procedure

Half of the water is combined with the sugar and brought to a boil. Allof the remaining ingredients are slurried together and then added to theboiling sugar and water. The temperature of this mixture is thenadjusted to 200° F. and held there for two minutes. The mixture is thenpoured into prepared pie crusts and allowed to cool and solidify.

The starch of the present invention is obtained in accordance withExample I above.

EXAMPLE 5

This example illustrates preparing brown gravy using the starch of thepresent invention.

The following ingredients and procedure is used:

                  TABLE IV                                                        ______________________________________                                                           % by                                                       Ingredients        Weight Present Invention                                   ______________________________________                                        Water              89.71                                                      Present Invention  5.00                                                       Hydrolyzed Vegetable Protein (1)                                                                 2.13                                                       Maltodextrin       1.42                                                       Hydrogenated Soybean and                                                                         1.00                                                       Palm Oil (2)                                                                  Beef Flavoring (3) 0.42                                                       Salt               0.25                                                       Caramel Powder (4) 0.02                                                       Onion Powder       0.02                                                       Black Pepper       0.02                                                       Garlic Powder      0.004                                                      Ribotide Flavor Enhancer (5)                                                                     0.006                                                                         100.00                                                     ______________________________________                                         (1) Fidco #42BE, commercial product sold by The Nestles Co.                   (2) Crisco, commercial product sold by Proctor and Gamble.                    (3) #R6090, commercial product sold by Haarmann and Reimer.                   (4) AP#680, commercial product sold by Sethness Product Co.                   (5) Commercial product sold by Takeda Chemical Industries, Ltd.          

Procedure

All of the dry components are admixed and then water is mixed into thisdry admixture. Next, the oil is mixed in and the mixture is heated to190° F. while mixing is continued. Once the mixture reaches 190° F. itis held at that temperature for five minutes.

This example illustrates making a bavarian cream pie using starch of thepresent invention.

The following ingredients and procedure is used:

                  TABLE V                                                         ______________________________________                                        FILLING                                                                       Ingredients   % by Weight Present Invention                                   ______________________________________                                        Whole milk, fresh 3.5%                                                                      72.794                                                          Sugar, fine grain                                                                           17.586                                                          Salt, Flour   0.101                                                           Present Invention                                                                           5.410                                                           Banana Flavoring                                                                            0.300                                                           Egg Yolk, fresh                                                                             3.809                                                                         100.000                                                         ______________________________________                                    

Procedure

All of the pie filling ingredients except for egg yolks are combined andcooked at 195° F. for 3 to 5 minutes. Then the ingredients are cooled to120° F. with constant stirring. Next, egg yolks are added and theadmixture well blended. This mixture is then added to a conventional piecrust and allowed to cool to room temperature before serving.

Although the use of the present invention has been disclosed primarilywith respect to foods, this is not deemed to limit the scope of thisinvention. The present invention can be used in other fields of industrysuch as paints, plastics, paper, wallboards.

It will be understood that the claims are intended to cover all changesand modifications of the preferred embodiments of the invention hereinchosen for the purposes of illustration which do not constitute adeparture from the spirit and scope of the invention.

What is claimed is:
 1. A substantially pure starch extracted from astarch bearing plant having a waxy shrunken-1 genotype.
 2. The starch ofclaim 1 wherein the plant is maize.
 3. The starch of claim 1 in granularform.
 4. A sol comprising water and an effective amount of substantiallypure starch extracted from a starch bearing plant having a waxyshrunken-1 genotype.
 5. The sol of claim 4 wherein the starch is presentin the range of about 1 to 20% by weight.
 6. A foodstuff comprising afoodstuff, and having as an essential ingredient therein an effectiveamount of substantially pure starch extracted from a starch bearingplant having a waxy shrunken-1 genotype.
 7. The foodstuff of claim 6wherein the starch is present in an amount effective to providefreeze-thaw stability to the foodstuff.
 8. A method for producing asubstantially pure starch from a maize plant having a waxy shrunken-1genotype comprising wet milling kernels of said maize plant to obtainsaid starch.
 9. The method of claim 8 wherein wet milling comprises:(a)steeping said maize kernels; (b) grinding said steeped maize kernels;(c) separating said starch from said ground maize kernels.
 10. A methodfor making a sol with a substantially pure starch extracted from astarch bearing plant having a waxy skrunken-1 genotype comprisingforming a slurry comprising water and an effective amount ofsubstantially pure starch extracted from a starch bearing plant having awaxy shrunken-1 genotype; cooking the slurry as necessary to producesol.
 11. The method of claim 10 wherein the step is conducted at atemperature equal to or greater than the gelatinization temperature ofsaid starch and subject to shear.
 12. A method for making a thickenedfoodstuff comprising combining a foodstuff, water and an effectiveamount of substantially pure starch extracted from a starch bearingplant having a waxy shrunken-1 genotype and cooking said combination asnecessary to produce a thickened foodstuff.
 13. The method of claim 12wherein the starch is extracted from a maize kernel.
 14. A method formaking a thicknened foodstuff comprising:(a) forming a slurry comprisingwater and an effective amount of substantially pure starch extractedfrom a starch bearing plant having a waxy shrunken-1 genotype; (b)cooking the slurry as necessary to produce a sol; and (c) combining thesol with a foodstuff to produce a thickened foodstuff.
 15. The method ofclaim 14 wherein the cooking step is conducted at a temperature equal toor greater than the gelatinization temperature of the starch andsubjects the starch to shear.
 16. The method of claim 14 wherein theplant is maize.